The invention relates to a section of a body of a vehicle including a flexible material outer skin that is tensed at least over one part of a frame of the vehicle. The invention also relates to a process of changing a configuration of such a flat section.
An at least partially movable outer skin of a motor vehicle is known from German patent application DE 100 26 264.3. To be able to move this outer skin, an actuator consisting of a polymer and/or ion-exchanging material and/or a material exhibiting various conformations is provided. This material is movable as a result of physical or chemical effects.
It is an object of this invention to create an outer skin of a motor vehicle body in which the tooling costs required for manufacture are very low.
This object is achieved by providing at least one mechanically moveable adjusting element provided beneath or on an edge of the outer skin so as to enable the outer skin to be deformed.
A flat section of an outer skin of a motor vehicle body consists of flexible material. A flexible material, such as a material for a convertible top cover, can be moved easily, but its surface cannot be increased. This material is tensed at least over a portion of a motor vehicle frame, for example a space frame. Pursuant to the invention, at least one mechanically movable adjusting element is provided beneath or on the edge of the section, enabling the outer skin to be deformed. The adjusting element is normally connected with the vehicle frame. The outer skin, for example, can be tensed by a bow, which can be displaced in a linear fashion.
By replacing classic outer skin parts made of sheet metal with a flexible outer skin, expensive sheet metal forming tools are no longer required. The weight of the outer skin is reduced considerably because flexible materials, such as cloth tissues, have a considerably lower weight than corresponding sheet metal components. The tight design limits for outer skin parts made of sheet metal with regard to package as well as regarding a formal integration of additional functions also no longer apply to the invented flexible outer skin parts. Through the possibility of active deformation of the outer skin, movable outer skin parts that so far used to be separate can also be integrated now. Due to this integration, gaps and/or joints, which are undesirable for visual appearance and usually require a lot of sealing efforts in order to avoid corrosion, do not arise any more with a single outer skin component. Furthermore, fast and inexpensive repairs are possible, because not all the various outer skin parts must be kept in inventory; instead, only a single roll of the flexible material is sufficient for all the different outer skin parts. The actual replacement is also simple in the case of an outer skin made of flexible material, and can thus be done quickly and is less cost intensive.
Beneficially, the flexible material has elastic properties, i.e. the surface of the material can be enlarged. Typical flexible materials with elastic properties are, among other things, stretch materials, latex, and all elastomers. A flexible and elastic outer skin of a motor vehicle body enables the molded design to be even more free than an outer skin that is only flexible.
Ideally, the elastic section of the outer skin can absorb impact forces during an accident. This represents a very simple, inexpensive and elegant possibility for achieving so-called pedestrian impact protection. With a skilled design, no separate components are required any longer. The vehicle passengers can also be protected during a crash when the outer skin of the body has energy-absorbing characteristics.
On one edge of the section, a strip is beneficially attached, which strip can be fastened to a component that is firmly attached to the body through a clip connection. The strip can, for example, be glued to the edge of the section, be welded to it or, pursuant to a particularly suitable further development, be sewed onto the edge of the section. For this purpose, the strip is favorably made of plastic. A sewing needle, for example of an industrial sewing machine, can effortlessly penetrate a strip that is made of a thermoplastic and not too thick. The clip connection of the strip with the component that is attached to the body can be designed such that the attached component represents a type of rod onto which the strip can be clipped with a clip section that contains a channel with a C-shaped cross-section. This clip section then encloses the rod in the clipped-on section in a form-fit manner, at least in part.
High forces can act upon such a clip connection, in particular with the use of a pre-tensioned section with elastic properties. In order to lower these forces acting upon the clip connection, the section can be tensioned in the vicinity of the clip connection in the direction of the force across a portion of the vehicle frame or through an adjustment element in such a way that frictional forces occur in the contact regions between the vehicle frame and/or the adjusting element and the section. The forces that are applied onto the clip connection are hereby reduced roughly by the occurring frictional forces.
At least one adjustment element can beneficially be moved in a translatory and/or rotatory fashion. For example, pneumatic, electric, piezo-electric or hydraulic adjusting elements are available as standard components for translatory and rotatory movements. Through the combination of several of these standard adjusting elements, any motion-related kinematics can be achieved without requiring a complex special design for the adjusting element. Alternatively, adjusting elements that are moved solely by the air flowing around the vehicle while in motion are also possible.
A coupling of the movement of an adjusting element to the vehicle speed is also possible. In particular when the section of the outer skin is important for the aerodynamics of the vehicle, it can be desirable to be able to deform the section as a function of the vehicle speed. In this way, for example, a spoiler only develops its effect at high velocities. At low speeds, such a spoiler, which usually does not contribute positively to the visual beautification of a vehicle, does not necessarily have to be visible.
In a beneficial further development the section can be deformed in the rear area of a vehicle by at least one adjusting element such that it generates an aerodynamic drive similar to a rear spoiler. A spoiler designed in this way can be displaced between a resting position and a usage position.
Pursuant to a favorable embodiment, the adjusting element can be seated eccentrically and/or have an elliptic cross-section so that the outer skin can be deformed in the rear area of the end section of the tailgate in such a way that an aerodynamic drive is created.
Ideally, the adjusting element is swiveled as a function of the respective vehicle speed. Aerodynamic set-ups and designs of the body increase its efficiency considerably with increasing vehicle velocity. At low speeds, such as for example in city traffic, the effect that can be achieved is very low, while particularly at low speed the less appealing appearance is especially visible. Therefore it makes sense to swivel the adjusting element only at higher vehicle speeds. Due to the swivel motion, the required storage space is also lower compared to a translatory motion. In this way the storage space beneath the tailgate is impaired less.
In order to increase the effect further, ideally, two swiveling adjusting elements can also be provided. These two adjusting elements can be arranged next to each other, or the second adjusting element can be arranged on a movable section of a first adjusting element. Depending on the configuration, either a particularly large spoiler or a spoiler with a particularly large travel path can be implemented.
In a favorable embodiment, the spoiler and a surrounding area on the body side is covered with the section made of a flexible and elastic material, which forms the outer skin. A gap is incorporated between the movable spoiler and the surrounding area on the body side. In familiar spoiler arrangements, this gap is very difficult to seal and disrupts the visual appearance. By covering the spoiler and the surrounding area on the body side with the flexible and elastic material neither sealing is required nor is the visual appearance impaired by a visible gap. The flexible and elastic material forms the outer skin and covers the gap so that no water can penetrate into said gap. The surface quality and paint of the body and spoiler parts located beneath this outer skin have to fulfill considerably lower requirements because contrary to familiar body and spoiler parts they do not form the visible outer skin. These parts can therefore be produced with less effort and thus lower cost implications.
Ideally no marginal sections of the spoiler can be made out on the outer skin made of flexible and elastic material, regardless of the position of the spoiler. The drastic difference in height between the spoiler in the used position and the surrounding area on the body side is solved in a visually very appealing way through a continuous transition area on the outer skin, which stretches all the way across. When the spoiler is shifted from its one final position into the other final position, it must be ensured that the flexible and elastic material that stretches across is sufficiently ductile so that it can tolerate this displacement even in the case of larger travel paths and still does not flap.
The spoiler can be both a front and a rear spoiler. It is particularly advantageous with a rear spoiler if the surrounding area on the body side is a conventional tailgate with a recess for the spoiler. Through the essentially conventional area on the body side beneath the outer skin, existing stiffness and thus also crash requirements are fulfilled. It is also possible in this way to attach hinges or a lock in the usual way. Another advantage of such a sub-structure is that, even when the outer skin is slit open, no objects can be removed from the trunk space located beneath.
In a favorable embodiment the spoiler forms at least in part a rear edge of the tailgate. To improve the aerodynamic properties of a vehicle, the generation of an aerodynamic negative lift on the rear axle is important. A sharp flow disruption edge on the rear edge of the tailgate is particularly suited for this. Such a sharp flow disruption edge, however, cannot be incorporated in the sheet metal of the tailgate without a lot of effort. By contrast, a spoiler that forms the rear edge of the tailgate at least in part can contain such a sharp rear edge. Usually, the spoiler in this design will not only form exclusively the sharp rear edge but also narrow strips of the two adjoining areas of the tailgate. In such a spoiler, a taillight is also easily integrated in the area of the rear edge. The outer skin stretched across must then be left open in the area of the taillight.
Depending on the spoiler position beneath the flexible and elastic material, the appearance of the entire tailgate can be modified substantially. For example, at low speeds when the spoiler is in the resting position, the tailgate can appear rather rounded and with a flowing outline. However when at higher speeds the spoiler is shifted from the resting position into a used position, the design of the tailgate can change into a very sporty tail with a sharp flow disruption edge.
The flexible and elastic material ideally has a magnetic coating. Through the magnetic coating the outer skin rests against the spoiler and the surrounding area on the body side in an adhesive manner if they consist of an iron metal. This can also prevent an undesirable fluttering of the outer skin at high travel speeds.
In another favorable further development the flexible and elastic material is additionally stretched across at least one rod, which is attached to one end of the spoiler. The rod will automatically move with the displacement of the spoiler. Apart from the spoiler and the surrounding area on the body side it will therefore contribute considerably to the shape of the outer skin and thus to the visual appearance. For this purpose the rod can also take on a bent shape, which depending on the spoiler position tenses the flexible and elastic material in a certain shape. To prevent this rod from being visible when the spoiler is in the resting position, an impression is arranged in the surrounding area on the body side in which the rod can rest. The impression is then covered with the tensed outer skin so that it is not visible.
Since the one end of the rod is firmly attached to the spoiler, relative motions are created in the other end of the spoiler to the surrounding area on the body side when the spoiler is shifted. This end of the rod is thus beneficially connected with a slide, which can be displaced on the surrounding area on the body side. This slide, being a purely functional component, should not be visible if possible. For this purpose the slide is beneficially located in an impression in the surrounding body-side area, across which the outer skin stretches, so that it is not visible from the outside.
Ideally the rod can consist of a similar material as tent poles, for example of fiberglass, aluminum, composite materials, steel etc. Such materials are light, robust, weather-resistant and yet slightly elastic so that the risk of lateral buckling is relatively low. The rods beneficially exhibit a low-friction coating, such as TEFLON. Due to the low-friction coating the outer skin can slide smoothly across without flapping. In its cross-section it can have a rectangular, round, oval, tear-shaped or L-shaped profile.
In another beneficial embodiment of the invention the section of the outer skin in the form a rocker panel of the vehicle can be deformed by at least one adjusting element such that it improves the aerodynamics of the vehicle during travel. A rigid rocker panel cannot have an optimal aerodynamic design because otherwise it would impair the passengers when entering and exiting to an intolerable extent. The visual appearance of such a rigid rocker panel would be incompatible with the appealing design. This issue can be resolved with a displaceable rocker panel, which when the vehicle is stopped or traveling at low speeds is located in a resting position so that it is possible to effortlessly get in and out of the vehicle. It is only at higher velocities that the rocker panel shifts from the resting position into a used position, which ensures the desired aerodynamic effects. Additionally the vehicle's side walls become less dirty with such a rocker panel because at high speeds the dirt glides along on the bottom or the rocker panel and is not splashed and whirled up on the side.
To accomplish this ideally an adjusting element, which is seated displaceably about an axis beneath the section, is provided. The adjusting element deforms the outer skin in different fashions as a function of the angle position, while the axis runs substantially in the vehicle longitudinal direction. The adjusting element can have different radial extensions on the circumference around the axis. This is a particularly simple arrangement, which nevertheless combines all advantages of a displaceable rocker panel. Additionally the rocker panel can have a varying outline across its longitudinal extension, which is coordinated with the remaining vehicle, without requiring several separate adjusting elements.
In another beneficial embodiment the section forms a flap of a vehicle, which the adjusting element can open or close. A flap of a vehicle is supposed to cover something in the closed position, such as a trunk, an engine compartment or a filler neck. In the opened position of the flap by contrast the area that was covered before should become accessible as effortlessly and completely as possible. For this purpose one side of the section can for example be tilted away or be rolled up from one side. Alternatively in a favorable embodiment the section can include a slot, which the adjusting element can expand into an opening. Such a flap however can also be implemented with two sections pursuant to the invention. For a closed flap the edges of the two sections meet with each other so that practically no gap remains between them. To open the flap, the two edges are shifted away from each other in a relative motion so that the area covered beneath becomes freely accessible.
The two sides of the slot and/or the two sections at the location of the joint can favorably be connected with each other by a zipper or a clip connection. This ensures safe connection with a closed flap. At the same time these two connections can also be undone quickly and effortlessly so that the flaps can be opened without difficulty. A locking system can also be incorporated easily for example with an electric zipper or power-actuated clip connection.
Alternatively, along the slot and/or along the edges of the sections, a rigid strip can be attached to at least one section, while at least one of these strips can be displaced by at least one adjusting element. The rigid strip allows bringing the slot sides and/or the edges into a defined shape. This facilitates defined opening and closing of the flap. These rigid strips are also well suited as contact points for an adjusting element so that the flap can be opened or closed also with power actuation.
In another interesting application the section is inserted as an outer skin in a tailgate so that its length can be varied in the longitudinal direction of the vehicle when the adjusting element displaces the rear windows in the longitudinal direction. This way it is possible to increase the passenger compartment as needed by displacing the rear window backward or also to increase the trunk by displacing the rear window forward. This enables very flexible usage of the vehicle.
Equivalent to the use of the section as spoiler, the section can ideally also be modified in its aerodynamic shape as a front or rear component of a vehicle through at least one swiveling adjusting element. Front or rear components here represent parts, which are located on the front or rear end of the vehicle, and at least in part also represent the transition to the vehicle floor, such as for example bumpers. Aerodynamically particularly effective are front or rear components that are located just above the road. Such front or rear components, however, can accidentally be damaged easily, for example while parking the vehicle or leaving a parking spot close to relatively high curbs. Since such front or rear components like all aerodynamic components can really only exhibit their full effect at high speeds, it is useful that the front or rear components are shifted from a resting position into an active position by means of an adjusting element only at higher velocities.
In another favorable application the section can be lowered by means of an adjusting element as an underbody of a vehicle. The underbody should assume as favorable an aerodynamic shape as possible. As with all aerodynamic components, a noticeable effect only takes place at relatively high velocities. It is therefore useful to lower the underbody only beyond a certain speed. Since the section then covers both the exhaust system, including the catalytic converter, and the rear axle drive, the section naturally must be able to withstand also accordingly high temperatures. Additionally the section must not be affected detrimentally by kicked-up rocks.
In a particularly attractive application the section is one piece and represents a fender and an outside door panel at the same time, while the door represents the adjusting element. This eliminates the gap between the front door edge and the adjoining fender and considerably improves the visual appearance.
Also very effective is the use of the invented section as an outside door panel, whose height of the upper edge of the actual door body can be adjusted with an adjusting element. This way the height of the door's top edge can be varied. If desired and depending on the weather a particularly low top edge can be selected for example in nice weather and good mood or a particularly high top edge in poor weather or bad mood.
The section pursuant to the invention can beneficially also be used as a fender and wheel well. The section is then attached both to the chassis as adjusting element and to the body. The visible gap between wheel and wheel well can thus be kept very small without limiting travel of the wheel. This represents a considerable visual improvement. However the aerodynamic effect should also not be underestimated because the wheel well is a much more closed unit so that less undesirable air turbulence is created.
In a much more developed version the section can be displaced by means of an adjusting element as the vehicle roof with the rear edge in the longitudinal direction of the vehicle. Such an embodiment makes it possible for one to either enlarge the size of the passenger compartment or the trunk, and secondly the visual appearance of the entire vehicle can be modified considerably.
In a very aesthetic and nevertheless simple embodiment the section can be deformed by at least one adjusting element such that depending on the position of the adjusting element the section covers a headlight and/or a radiator grill to varying degrees and/or different partial regions of the headlight and/or the radiator grill. Depending on the type of coverage of the headlight, the vehicle can assume quite different appearances. When the section for example covers the headlight especially from beneath, the vehicle (with the headlights being the eyes) assumes a rather friendly appearance. The section can basically serve as the eyelid and in accordance with a human face convey the vehicle's different expressions. The same also applies to the radiator grill, which basically corresponds to the mouth and nose section of a face.
In a favorable further development at least two sections are used, which cover a headlight and/or a radiator grill to varying degrees and/or different partial sections of the headlight or the radiator grill. The “facial expression” of the vehicle can be modified to even more varying degrees with two or more sections. The facial expression can be modified both as a function of the speed, e.g. sporty at high speeds, and also as a function of the driver's mood.
Beneficially a lighting device is installed beneath the invented section, with said device shining at least partially through the section. For simplicity reasons the lamp can also be attached directly to the section for this purpose. For example lamps such as indicators, brake lights etc. can be hidden beneath the section. When the lamps are not in operation, they are not visible beneath the cover. The problem with the gap and the sealing issue are also non-existent here because the lamps are located in a dry area beneath the section. Alternatively the lamps however can also be used to provide extensive back-lighting of the section. For example the color of the section can also be modified to the likes of the driver.
The invented section can be deformed in a particularly simple version also by at least one adjusting element, which is a plug element that can be inserted detachably into at least one socket that is firmly installed in the body, and forms a portion of the vehicle frame across which the elastic section is stretched. The term adjusting. element used in connection with the invention also includes these plug elements, which can be exchanged quickly manually by the user or in a repair shop. The cross-section and the shape of the plug elements can be ideally selected freely. Similar to the Smart vehicle, the appearance of the vehicle can thus be modified effortlessly, for example by exchanging a few plug elements with others of a different shape beneath the section. The entire shape and characteristic of a vehicle can thus be modified considerably in next to no time.
Flexible folding tops for convertibles made of textiles are generally known. Such a folding top is described for example in European publication EP 0 530 134 B1. This top contains, among other things, textile tissue zones made of elastic rubber fibers, which are elastically ductile in length. With regard to length, elastically ductile tissue zones have to absorb only few forces.
Additionally, with regard to length, elastically ductile tissue zones are arranged such that they are normally covered, i.e. not exposed directly to UV light.
If now entire sections of the outer skin of a vehicle body are supposed to be made of an elastic material instead of sheet metal, this material must exhibit a very high resistance to tearing. Additionally, to avoid undesired noise and undesired aerodynamically caused flattening and wobble appearances, the material should be attached in a pre-stressed fashion, wherein it must never lose this pre-tension. Familiar tissues made of elastic rubber fibers are not suited as a material that has to exhibit a high resistance to tearing because they do not achieve the required elastic expansions.
A suitable section pursuant to the invention for a visible outer skin of a vehicle body can consist of a flexible planar textile formation, which is coated at least on the visible side. The planar textile formation represents the actual supporting layer. It is responsible for the stiffness, firmness and the associated protection from vandalism.
Textile planar formations can be tissues, knitted fabrics or fleece. A tissue consists of two fiber systems crossing perpendicular to each other, of which the chain (warp) runs vertically and the filling (woof) horizontally. The quality of a tissue depends, apart from the crossing of the fibers, on the material, thickness and type of thread, the finish, color, durability, pliability, stiffness, firmness and haft. Tissues for structural applications can generally be expanded only insignificantly in the longitudinal and transverse directions and are therefore less suited for the elastic material pursuant to the invention. Ductile tissues, which fulfill the required reversible ductility, however, can also be realized on the basis of highly ductile, for example texture-proof, threads. A fleece or a mat consists of randomly arranged filament yarn or staple fibers. Since the fibers here are arranged randomly, such a textile formation can have the undesired effect that it fluctuates heavily in its properties. Additionally a fleece does not exhibit a distinct spring-back behavior. Knitted fabrics are made of stitches and are produced on hosiery or knitting machines. Compared to a knitted fabric, fabrics have additional cross-connections between the stitches. Knitted fabrics expand well in the longitudinal and transverse directions. Fabrics, however, exhibit slightly different characteristics in the longitudinal and transverse directions. Ideally the planar textile formation therefore is a knitted fabric or a fabric. In the case of a knitted fabric, additionally, a unidirectional woof for reinforcement purposes can occur, i.e. additional fibers or threads can be introduced into the textile formation in one or more directions.
The elasticity of the material however is determined not only by the textile structure, but also by the material of the fibers and/or threads of which the textile formation consists. In order to achieve a very high resistance to tearing despite the elastic ductility, the elasticity should preferably come exclusively from the structure of the textile formation and not from the material of the fibers and/or threads of the textile formation. Therefore only relatively firm fibers can be considered, such as for example of polyamide, polyethylene teraphtalate, polyethylene, aramide fibers or steel fibers. Fibers made of polyamide have a low light fastness and are slightly hydrophobic and expensive. Beneficially the fibers are made of polyethylene teraphtalate (PES or PET). PES is a high-tensile material, has a low creep tendency, and its shrinkage can be adjusted. It takes on color well, and there is a broad spectrum offered. Availability is high, and the desired properties can be adjusted well through additives. Polyethylene by contrast, although it is extremely firm and highly tenacious, is very expensive, hydrophobic and has a low melting point as well as a distinct creep tendency. As a further development of PES, PEN of course is also very well suited. PEN has just slightly higher mechanical properties and a lower creep tendency. Aramide fibers are extremely tenacious, firm and temperature-resistant, but expensive, hydrophobic and have poor adhesive properties. Steel fibers are high-tensile and tenacious materials and are corrosion-proof. However they are expensive and problematic in their processing. Aramide fibers and steel fibers are therefore unsuited as sole materials, but can be admixed in order to increase protection of the textile formation against vandalism.
In the textile formation furthermore additional fibers can be integrated, which serve the purpose of sensors and/or actuators. For example, non pre-published German patent application DE 101 10 329.8 describes textiles into which fiber-optic fibers are introduced, which can be illuminated by a light source. From likewise non pre-published German patent application DE 100 29 237.2, a seat heater is known, which heats up locally only in areas in which a passenger actually applies pressure on the seat. For this purpose appropriate wires, which under load generate a contact with each other, can be woven into the textile seat cover.
The coating can be waterproof and represent the necessary protection from UV light. The coating is also responsible for wear and tear resistance as well as for appearance. The appearance includes not only the actual appearance, but also to what extent dirt is rejected by the coating or at least can be removed from there easily. It is only through the combination of a planar textile formation with the coating that all requirements regarding tear resistance, weather resistance, wear resistance and reversible elastic pre-tension ability can be fulfilled.
The coating consists favorably of an adhesive layer, an aromatic intermediate layer and an aliphatic top layer. The adhesive layer guarantees optimal adhesion of the coating to the textile tissue. The aromatic intermediate layer ensures water tightness and UV resistance, and the aliphatic top layer generates the desired visual outer appearance. Since the invented textile formation in vehicles is supposed to replace especially outer skin parts made of sheet metal, above all an appearance that is similar to a painted sheet metal surface is desired. For this, surfaces with different levels of luster (matte to high gloss) and with different levels of roughness (smooth or structured) are used.
Further beneficial embodiments form the subject matter of dependent claims.
The drawings depict several exemplary embodiments of the invention, which are described more closely in the following.